The present invention relates to an apparatus for removing stone and gravel contained in excavated soil by a sieving operation.
As is well known, soil at the foot of a volcano, mountainous land or the like contains a lot of stone and gravel. Unless stone and gravel are removed therefrom, there is no possibility of utilizing such a vast area as arable land, meadow or the like. Heretofore, land improvement works including removal of stone and gravel from excavated soil have usually been conducted in the following manner.
First, waste land is excavated with the aid of a power shovel or the like. Next, the excavated soil is sifted to separate stone and gravel therefrom and then the sieved soil is conveyed back to the working land. Finally, a levelling operation is performed.
Typically, a rock picker, stone picker, stone collector or the like has been employed for carrying out a series of operations as mentioned above. But all of the conventional apparatus are constructed such that land excavation and removal of stone and gravel are carried out while the apparatus is being hauled or pulled by means of another power vehicle. Thus, the conventional machines have drawbacks that removal of stone and gravel is limited only within the surface layer of the ground and the removing operation is, therefore, conducted at a reduced efficiency.
Specifically, the conventional equipment is designed and constructed such that land excavation and removal of stone and gravel are simultaneously conducted exclusively for the purpose of ensuring a high operating efficiency, but this type of design and construction results in reduced capability in removing stone and gravel. Further, an additional drawback with the conventional equipment is that operation is performed with much difficulty on an incline, because it is hauled or pulled by means of another power driven vehicle when it is moved to another place for further operation.